Fragrances used in cosmetics and personal care products increase the esthetic appeal of the product by masking or covering the base odor of the ingredients comprising the product. In most cases, the fragrances are blends of a number of natural or synthetic chemicals, which when blended together produce a characteristic aroma. The fragrance is essentially an inactive ingredient of the product, being added to enhance its esthetic appeal.
A fragrance component of a particular product may contain also one or more essential oils or chemical compounds having a claimed therapeutic effect. In such cases, the essential oils or chemical compounds reportedly produce, create or cause an emotional or physiological change when the subject inhales the aroma of the fragrance. Here, the fragrance is an active ingredient of the product, and the product for this purpose is often called “aroma therapy.”
Such fragrances may be found in aqueous and non-aqueous liquid, creams, lotions, gels and pastes, as well as in powdered compositions. When fragrances are added to products of this nature, the fragrance often degrades or changes with time, and creates an undesirable odor, or, in some cases, a pronounced color change in the product containing the fragrance.
Without being bound by any theory or particular mechanism, the degradation of the fragrance is believed to be caused by chemical reaction among the various components of the fragrance and the components comprising the base product. These chemical reactions are cumulative, and are enhanced by exposure to heat, light, and sometimes the atmosphere.
The degradation of fragrances also occurs in powdered products, particularly those containing granular salts, such as sodium chloride, magnesium sulfate, sodium sesquicarbonate, and sodium bicarbonate. In such products, the fragrance is generally sprayed directly onto the surface of the salt or salts during a dry blending process.
The degradation of the fragrance in powdered products in most cases is more pronounced than in aqueous and non-aqueous liquid products. They may develop an undesirable odor or discoloration, particularly in products containing sodium chloride, whether alone or in combination with other salts having large particle sizes, i.e., greater than 20 mesh (0.85 millimeter).
Typical powdered products of this type include bath salts, body and foot soaks, body and facial masques and other cosmetic and personal care products. As noted above, these products may be simply esthetically fragranced or may be intended for use in aroma therapeutic applications.
It would therefore be desirable to provide a formulation and method of manufacture which addresses the problem of fragrance decomposition or degradation.